Tens of thousands of fun runners and amateur athletes set off in bright sunshine in the 32nd London marathon.

Up to 37,500 athletes are expected to finish the 26.2-mile course through the streets of the capital to earn their marathon medals and raise money for countless charities.

As well as the elite athletes and fun runners, a host of celebrities crossed the start line in support of good causes.

Newsreader Sophie Raworth, 43, revealed she is running in aid of St John's Ambulance after collapsing during last year's event.

She told the BBC: "Last year I was 24 miles in and not feeling great. It was quite hot and my heart was going extremely fast. I woke up on oxygen with a temperature of 106 degrees.

"It took me over six hours last time so if I don't shave a bit of time of my personal best then I'm giving up."

Rugby league stars Steve Prescott and Paul Sculthorpe are hoping to complete a gruelling eight-day challenge by completing the marathon on Sunday. Prescott, 38, was diagnosed with a rare form of stomach cancer in 2006 and is aiming to raise £16,000 for his charitable foundation.

The former St Helens players have already completed the Paris marathon, cycled 184 miles through France, and kayaked across the English Channel. The pair then pedalled another 82 miles before setting off for the marathon today.

Speaking to the BBC, Prescott said: "We're pretty tired but it's been an incredible journey." Sculthorpe added: "He's an inspiration and when Steve asked me to take part, how could I refuse?"

James Cracknell, a double Olympic gold medal winner with the British rowing team, is aiming to continue his remarkable record of physical feats by running a third sub-three hour marathon.

The athlete recovered from a life-threatening head injury suffered while attempting to cycle, row, run and swim from Los Angeles to New York in under 16 days.

Cracknell told the BBC: "I'm running for the Children's Trust which helps children with brain injuries and provides support for their families.

"What I go through on a daily basis is nothing compared to what they are going through."

Despite dry and bright weather when the race got under way, forecasters have warned of rain later on. It should also be the perfect temperature for participants, with highs of around 13C expected.